With the rear body removed, it was easy to access the rear suspension. This consists of a Boge self-leveller unit, which is linked to a lower ball joint. Two steel "arms" form a sort of A-frame between this lower ball joint and the chassis.
The Boge self-leveller is intended to act as a sort of self-pumping suspension. As the loaded vehicle moves up and down, the Boge will maintain the level of the vehicle as though it were unladen. Here's the upper part of the Boge unit, and a shot of the lower ball joint:
The A-frame and Boge unit were removed from the vehicle. The next photo shows the state of part of the A-frame once removed from the chassis (as is normal with this sort of thing, I had to use the angle grinder to cut through a couple of the seized bolts in order to remove them):
Fortunately the dirt and rust were only surface-deep, so the application of an angle grinder with wire brush attachment soon took care of it!
The Boge unit was the next item to be cleaned. New rubber gaiters were ordered because the existing ones were perished.
With later models of the 110 and Defender, the rear ball joint for the A-frame appears to have a grease nipple fitted; mine didn't, so I fitted one for ease of later servicing. I just carefully drilled a small hole in the centre of the ball joint, tapped the thread, and then fitted the grease nipple.
The A-frame ball joint itself had a bit too much play, so this was replaced. The Boge unit was then primed and painted.
Here's the end result: renovated A-frame struts and brackets.